Many can not spend much on weekly/monthly groceries, so they have to settle for less than healthy foods because that is what they can afford.

I don't think this is necessarily true though. I read a blog that was talking about the price of cereals, for example. Ounce for ounce they are SO MUCH more expensive than buying regular grains, like oatmeal or cracked wheat. Sure, they take more time to prepare, but they are cheaper and a lot healthier than the stuff in the cereal aisle.

Also, some of your ready-to-cook meals like Rice-a-roni or pasta where you just add water (those instant-type meals) can be made cheaper if you buy plain rice or pasta and add your own seasonings. It takes more work, but again, it's cheaper.